Incidence and Risk Factors of Postoperative Delirium in Elderly Patients Following Hip Fracture Surgery: A Nationwide Retrospective Cohort Study in Taiwan.

BACKGROUND: Delirium is an acute cognitive change characterized by behavioral and psychological features, such as visual and auditory hallucinations, sleep disturbances, and emotional confusion. It can lead to extended hospital stays, increased mortality risk, and higher nursing costs. In postoperative hip fracture patients, delirium results in a higher complication rate, poorer functional recovery, increased readmission rates, repeat surgeries, and elevated mortality. Despite these serious consequences, the literature provides limited information on the incidence of postoperative delirium following hip fracture surgeries in Asians. Additionally, there is a lack of long-term, comprehensive nationwide population-based studies, highlighting an important area for future research. This study aims to understand the incidence and risk factors of postoperative delirium in hip fracture patients using representative population data. METHODS: We conducted a retrospective cohort study using the Taiwan National Health Insurance Research Database (NHIRD) from 2009 to 2020. The cohort consisted of 118,682 patients aged 65 years or older who were diagnosed with hip fractures. The delirium incidence was observed per 1000 person-years. The Cox proportional hazards model was used to investigate the incidence of delirium among hip fracture patients. RESULTS: The incidence of the first episode of delirium after hip surgery in the elderly was 1.87 events per 1000 PYs. Factors associated with delirium included being female (adjusted hazard ratio [aHR]: 0.59; 95% confidence interval [CI]: 0.53-0.64), age ≥ 95 years (aHR: 3.52; 95% CI: 2.74-4.51), comorbid dementia (aHR: 2.63; 95% CI: 2.38-2.92), and ICU stay 2-3 days (aHR: 2.85; 95% CI: 1.28-6.37). The occurrence of delirium was significantly associated with an ICU stay of ≥ 4 days, dementia, as well as 30-day, 90-day, and 1-year mortality (p < 0.001). CONCLUSIONS: This study highlights the relatively low incidence of postoperative delirium in elderly hip fracture patients in Taiwan. Key risk factors identified include advanced age, female gender, comorbid dementia, and prolonged ICU stays. These findings underscore the need for targeted prevention and early intervention strategies to improve patient outcomes.